1. Field of the Invention
The invention relates to a skylight having a case, wing and weight-balancing device and having at least one pneumatic spring. More particularly, the invention relates to a skylight where the pneumatic spring is pivotably attached at one end to the case and to the wing at its other end. Thus the wing, after being unlocked from the case, automatically opens under the effect of the pneumatic spring and when the stroke of the piston rod is fully extended from the cylinder of the pneumatic spring, the wing is brought into an emergency open position in which the opening of the case is entirely exposed.
2. Description of the Prior Art
In skylights which may be used as emergency exits, the weight-balancing device generally comprises pneumatic springs which exhibit strokes allowing for a relatively long extension of the piston rod out of the cylinder. When the wing is opened, the size of the opening is controlled by the angular position of the wing relative to the case. In the emergency opening position, the angle between the opened wing and the surface plane of the case is generally in excess of 90.degree.. In this arrangement, the wing is designed as a wing or flap and is hinged to the rear of the case by virtue of hinges mounted on a horizontal rear spar of the case. Alternately, the wing may be pivotable by virtue of hinges mounted on the longitudinal spars on the sides of the case.
For a skylight whose wing is constructed as a flap or pivotable wing, the pneumatic spring can either be mounted directly to the frame of the wing or indirectly to the wing by an intermediate member. This intermediate member may be an extension cover which overlaps the wing frame. If the wing is connected to the case by means of an underframe, then the pneumatic spring can act upon the underframe such that, when the wing is unlocked from the underframe, the wing can be opened like a wing flap. When the lock holding the wing to the underframe is released, it opens in a swinging fashion by pivoting about a horizontal hinge axis along the top of the underframe.
With traditional skylights, in their preferred construction for residential ceilings or attic spaces, the width or size of the opening for the wing is restricted. The pivoting wing or flap, when partially open, protrudes into the recess of the case partially blocking the opening and thereby restricting the free passage width of the case.
With skylights providing roof access, for example, for a chimney sweep or for an emergency exit, the opening so formed by the fully opened wing is to large to permit its use as a ceiling window. This is because such a skylight does not provide any adjustment for smaller angles for opening the wing as would be necessary for ventilation or viewing purposes, which angles must also, in particular, be storm-proof.